Optical thermometric properties of square-like KLa(MoO4)2: Yb3+/Er3+ up-converting phosphors

Square-like KLa(MoO₄)₂: Yb³⁺/Er³⁺ mono-disperse crystals were synthesized by hydrothermal process. Their up-conversion luminescence (UCL) emissions were contributed by green (²H_11/2/⁴S_3/2 → ⁴I_15/2) and red light radiation (⁴F_9/2 → ⁴I_15/2) transitions of Er³⁺ under 980 nm. Energy transfer (ET) from Yb³⁺ to Er³⁺ were proved by the lifetimes of green emissions and the UCL mechanisms were also discussed according to power-dependent UCL intensities. The optical temperature sensing characteristics were explored by thermal coupled levels (TCLs) of Er³⁺ (²H_11/2/⁴S_3/2 → ⁴I_15/2) from 283 to 493 K and the sensitivity reached 1.7 × 10⁻² K^-1 at 493 K. The results indicate that the phosphor KLa(MoO₄)₂: Yb³⁺/Er³⁺ as a kind of potential candidates could be applied to the electronic components temperature sensing.